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Hey guys I'm Nate welcome back to the workshop today. We're going to be taking a little bit of a look at ferrofluid. That's a liquid
That's attracted to magnets and make some really cool shapes when it's in a magnetic field the basic recipe for our
ferrofluid that we'll be making today is one that I got from a channel called brainiac75 they've got a lot of cool videos about
Ferrofluid so if you're interested in seeing more go check them out before we start making our ferrofluid
I wanted to talk a little bit about what it is
And why some recipes do and don't work the basic idea of a Ferrofluid is a liquid
That's attracted to a magnetic field
This is done by suspending a ferrous chemical inside a liquid base toward properly a ferrofluid needs at least three main components
The first is a magnetic powder that can be suspended in the fluid will be using magnetite a synthetic black iron oxide
Once we have our magnetic powder base
We need a fluid to
Suspend it in and this is where it can get a little bit tricky; an issue we quickly run into is that most liquids will
Not stick to the microscopically small particles that make up our magnetic powder
We may be able to get our powder wet, but as soon as a magnet is introduced all of the particles will stick together
So closely that there's no longer any space in between the individual ones for our fluid base
Let's see what happens if we try mixing our powder with plain water
This cup now has a mixture of a little bit of water and some of our
Magnetite powder you can see that it hasn't mixed in very thoroughly at the bottom
There's still sort of a thick goopy paste with a thinner
black liquid on top of it now this thinner liquid does have our magnetite suspended through it pretty well at this point
So you might think hey that should work won't that be magnetic well watch what happens when we actually put a magnet up against it
Look at that it squeezes the magnetic powder so much that it just pulls all of it right out of the water. You can see
We are now getting water that's almost clear again. We've just pulled all of the magnet powder right out of there
It does look kind of cool though. You can see all the magnetic powder flowing through the water
over to the magnet
So the water clearly doesn't work and that brings us to the third element that we need in our ferrofluid
and that's what's called a surfactant the word surfactant comes from a combination of the words surface active agent.
A surfactant is something that lowers the surface tension between two substances
What we're looking for is one that will work as a wetting agent to make sure that our liquid base will surround every individual particle of our magnetite powder
Motor-oil does exactly what we're looking for it's a liquid oil base with surfactants added to make it stick well to the surface of oil
This particular brand is the same kind that was recommended by Brainiac75 on his channel
But I've tried it with a couple of other brands of synthetic motor oil
And they seemed to work just as well
So now let's take some of our oil and some of our Mack type powder mix them together and see what happens
And how it's different from mixing it with water
Now we have our motor oil in the cup, let's add that get up outta to it until it becomes a fairly uniform consistency
There we go we now have a fairly thick liquid mixed up, and that is our Castrol Magnatec oil mixed with our magnetite powder
Let's see how our liquid responds to a magnet
There we go you can see is definitely getting pulled on to it there
And we're also even starting to get a few fun little shapes forming look at that
The walls of this cup get coated pretty quickly in our black paste so to make it easier to see let's pour our liquid out
Onto a plate and then see how it reacts to a magnet
Alright, let's move our plate over our magnet and see how this goes
Definitely see your reacting you're starting to get some of those cool. Little spiky shapes that we're looking for from the ferrofluid
That's pretty cool
All right now, let's watch what happens if I take the magnet away from the mixture
Just kind of puddle back down have all our fun little spikes
Take it away, and they all just smooth themselves right out
Now that's pretty neat, but this ceramic magnet is actually not all that powerful
So let's see what happens if we use something a little bit stronger
We've got four neodymium magnets all stuck together right here, and this should provide some pretty intense power
Hopefully not too much power. Let's see the result. I want to break my plate either. Oh
Boy yeah look at that
It's so close to the magnetic field and the magnetic field is so strong that we're not getting the normal points
We're looking for but we're just getting some interesting plate
Spots on the most concentrated bits in the magnet also see this little puddle of oil in the middle
That's what I was talking about by using magnets that are too powerful
It's actually squishing our magnetic powder together, so powerfully that it's squeezing the oil out from in between the particles
Try and take this magnet off and then back it away, so it's not quite as close to our magnet powder
We've added two more plates that should keep our magnets a little more separated from our ferrofluid now. Let's see how it reacts
We're still getting the four different concentrated points so our four magnets are clearly not all acting it has one powerful magnet
Which makes sense?
There we go look at that
Oh that's beautiful
Those spikes are fantastic
As long as I keep moving the magnet they sort of keep growing in the magnetic field
If I just hold the magnet still of course they don't move anywhere just to illustrate it. It's only when I'm moving the magnet
That the fluid is moving with it
Well that was a pretty powerful magnet now
I also have some ultra powerful knives these things are huge and so strong
I'm afraid it might be too strong and it might just pull the magnetic powder right out of the oil
But we got to try it
You'd still like fully an inch away. We're getting good results though spikes are giant
That looks so cool. Let's see what happens if I pull the magnet away. Well. We've got these giant spikes
Bloop huddled back down
back
We got sort of these like weird ridges instead of regular spikes
Not quite what I had in mind, but also kind of neat
There we have it our ferrofluid may not be quite so runny or thin as some commercially-available
Ferrofluids, but it does respond well to magnets and we do get those cool points sticking out of it
Just the way we wanted to. One more test
I want to try because I know a lot of you are gonna want to see it
Let's see what happens if we freeze it with liquid nitrogen
I have a prediction and I think the liquid nitrogen is going to freeze the motor oil and it'll become so rigid that it no
Longer responds to the magnets well
Let's find out now pouring the liquid nitrogen on just like this would be no fun
So let's try and get some good spikes on there, and then freeze those so if they stay even when we remove the magnet
All right those some good spikes put on the safety glasses
See about freezing our ferrofluid
Hopefully, it doesn't just shatter my plate. It's a very real possibility. I understand
Take away the magnet
Well I would say we've got some good frozen spice it's actually got a cool
You bet anymore to keep it nice and frozen
And normally without a magnet these things are just gone now, I've got some frozen motor oil and spike shaped
I can poke them
Now I got some of the unfrozen stuff on my magnet, that's annoying
There you go how to make your very own ferrofluid using magnetite powder and
Castrol Magnatec motor oil this stuff is pretty fun to play with although I do recommend you wear gloves because
Motor oil is designed to stick to stuff and this stuff is very black in color, so if you get any other than hands
It's going to be on your hands, and it's going to spread to everything you touch
It's really hard to get off even with soap and water if you've got any ideas on how to make ferrofluid
That's a thinner consistency more like the commercially available ferrofluid let us know down in the comments
I would love to try all of your ideas and if one of them works
We'll make an updated video showing you how to make that kind of ferrofluid
And we'll send you 25 bucks.
Well now we know that ferrofluid is made from a magnetic powder base a liquid base and some kind of surfactant.
Motor oil already has a liquid base and a surfactant in it so it bonds
Well to our magnetite powder to give us a ferrofluid liquid, nitrogen
We'll freeze our ferrofluid solid so it remains
Spiky even when we take our magnets away from it if you love these kinds of hands-on experiments
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Your motor oil looks like this in your car get an oil change
And talk to him the canopy
Ooh that part is not frozen at all. Gross!